1. Field of the Invention
The present invention relates to a medical diagnostic apparatus, and more particularly to a medical diagnostic apparatus using X-ray photography and having a length-adjustable arm structure.
2. Description of the Related Art
Generally, an X-ray diagnostic apparatus photographs an object using an X-ray to obtain an image of a diseased part of the object and diagnose the diseased part by reading the obtained image.
A diagnostic apparatus 90 shown in FIG. 9 is suggested as an example of the X-ray diagnostic apparatuses. The diagnostic apparatus 90 comprises an elevator unit 91 mounted to a main body 96 to be movable up and down by a built-in elevation actuator, an X-ray generation unit 92 mounted to one side of the elevator unit 91 to be movable through an arm 93, and an X-ray detection unit 94 mounted to the other side of the elevator unit 91 through a C-shape arm 95.
The X-ray generation unit 92 and the X-ray detection unit 94 are facing each other with respect to the elevator unit 91. Since the arms 93 and 95 are rotatable with respect to the elevator unit 91, X-ray photographing can be performed with a patient not only in a standing position but also in a lying position on a table if the patient is hardly able to carry him/herself and keep standing during the X-raying. In this case, more specifically, the patient is laid on the table and the X-raying is performed as the table is passed through a curve of the C-shape arm 95. Thus, the X-ray images can be photographed at various angles without directly moving the diagnostic apparatus or the patient.
Meanwhile, in the X-ray diagnostic apparatus, a certain range of a source-to-image distance (SID), that is, a distance from an X-ray source to a detector unit needs to be secured. Generally, about 1000˜1800 mm of the SID, more particularly, about 1800 mm when performing a horizontal photographing with the patient in a standing position to about 1000 mm when performing a vertical photographing with the patient in a lying position is required.
In the conventional diagnostic apparatus 90 as the above, a central axis of the main body is distanced to the C-shape arm 95 by about 1000 mm in order to secure the maximal SID for the horizontal photographing, and the C-shape arm 95 has at least an 800 mm length. On the other hand, while the maximal SID for the vertical photographing is 1000 mm, about a 1300 mm distance is required as a maximal elevating distance with a lowermost point of the elevator unit 91 guaranteed as well. Furthermore, the C-shape arm 95 of the conventional diagnostic apparatus 90 has a fixed length and is immovable.
As shown in FIG. 9b, the conventional diagnostic apparatus 90 has at least a 2.2 m height at the main body. In a position for the vertical photographing, where the table is passed through with the patient laid thereon, a distance from a mounting floor of the diagnostic apparatus 90 to an end of the C-shape arm 95 is at least 2.5 m.
However, since a floor height of general buildings is not greater than 2.5 m, such a conventional diagnostic apparatus is difficult to be installed in general buildings. In addition, when the lengths of the main body and the arms 93 and 95 are controlled for use in general buildings, the maximal SID is hardly achieved in case of performing the horizontal photographing keeping the patient in the standing position.
Accordingly, a diagnostic apparatus capable of guaranteeing the maximal SID for the horizontal photographing and facilitating the installation in buildings with a general floor height has been in need.